anyone ever made a Parsons turbine

[skyline1]

Does anyone know if a miniature Parsons type (axial flow) steam turbine has ever been made ?

I have had much success in small scale with DeLaval impulse ones but I am not sure about a full blown multistage reaction one.

I am thinking about maybe three or four stages H.P end being about 1" dia

Am I fighting the laws of physics even thinking about it ?

Ideas, materials, methods ?

All welcome

Regards Mark

 

[Mechanicboy]

Try this book by Harrison H. H. http://ia600308.us.archive.org/9/items/modelsteamturbin00harrrich/modelsteamturbin00harrrich.pdf ..

 

[skyline1]

Thanks Jens

Interesting reading,

Harrison's book is one of the ones that got me infected with "turbinitus"

It's a very passive illness and has no effect on physical health

but it makes you think, like Charles Parsons

WHAT IF!

Turbinia scared the heck out of the Royal Navy !

Regards Mark

 

[Mechanicboy]

Mark, it is a difficult project to make a Parson's turbine. I maked a steam turbine with reduction gear 10,2:1. Oil as lube to bearings is critical due internal friction in the oil.

Here are the tests of oils and measured revolutions per minute:
Work pressure= Mobil ESP 5W-30 / Air tool oil / Diesel oil (fuel for diesel engine as lubricant)

1 bar= 4700 / 13230 / 17600
1.5 bar= 6200 / 17900 / 25700
2 bar= 11400 / 21660 / 31500
2.5 bar= 15500/26340 / 36700
3 bar= 18600 / 28800 / 41800

As i can see the ball bearing get less friction with diesel oil as lucricant, it is sensitive for jet stream from nozzle. With high revolution above 15000, i can feel there are enough torque when trying to stop the turbine shaft.

I can think: With less friction means less waste of the steam and fuel for heating the boiler.

Here is my steam turbine under load in these movies.

[ame="http://youtu.be/IXT2rrGPYt8"]http://youtu.be/IXT2rrGPYt8[/ame]

[ame="http://youtu.be/K1DqyJnfaU8"]http://youtu.be/K1DqyJnfaU8[/ame]

 

[skyline1]

Hi Jens

Impressive little job, very powerful

I quite agree with you about bearing friction it can make a dramatic difference in little turbines like this. My latest has high speed ball races but I have had success with with plain sleeve bearings of cast iron with silver steel shafts. I tried bronze initially but at these high speeds they wear out very quickly

Regards Mark

 

[Mechanicboy]

I can recommend you use to the stainless steel ball bearing part number SKF W 618/4 in the steam turbine. Hold revolution high as possible and do not make too large turbine wheel and have the turbine wheel as a flywheel to make more torque in high revolution, use reduction gear who is between 10.2:1 and 12.2:1. Do not use whole number such as 10:1, 11:1 etc.. use to example 10.2:1, 11.2:1 or similiar to last the gear tooth longer life. Do not use too much oil in gear house due friction by oil, use thinn oil such as sewing oil or diesel fuel as lubricant.

 

[goldstar31]

Some years ago I sat through a lecture by 'someone' who was retired but a former very senior member of 'Parsons' in Newcastle upon Tyne. I'm ashamed to admit but I lost interest when it was claimed that Parsons had done his initial testing of his models in a village pond at his then home in Ryton on Tyne- which is about 7-8 miles from Parsons and 'Clarkies' and whoever.

Again there is now reference to 'ball bearings'. This raises questions about Turbinias and earlier models because- there are NO ponds in Ryton and I have serious doubts that anyone could have stuck ball races or whatever in his models then.

So why does a bloke leave a perfectly good factory environment to do his thing?

I'm not 'flying a kite' or whatever because--------------------I was born in Ryton's Urban District and I spent more lunch hours sitting beside the remains of Turbinia in what became the Exhibition Park in Newcastle.

Anyone comment, please?

 

[Cogsy]

I don't know if they are available small enough for your application, I've been out of the bearing game for a while now, but you may want to look at getting hybrid ceramic bearings from SKF. These bearings use ceramic balls made from compressed ceramic powder, and steel raceways. They can be lubricated with plain water, fruit juice, milk, grease, oil, virtually anything really. Extremely high speed and low drag. I have seen them used in RC jet engines supposedly up to 250,000 RPM running at extremely low lube levels.

 

[skyline1]

Hi Cogsy

I agree ceramic bearings would be ideal for this sort of thing. The model jet boys always use them and as you said they are running at very high speeds indeed much faster that steam turbines move at

They lubricate 'em with a little squirt of fuel tapped off from the main fuel supply, JET A is mostly paraffin (Kerosene) and a small percentage of gasoline (with about 5% castor oil apparently)

You can get them in very small sizes

The main problem is that they are scarily expensive probably about £75 - 100 EACH ! in these small sizes.

Regards Mark